Release films are widely used as peelable protective films for adhesive tapes or self-adhesive labels, in order to prevent sticking of these single- or double-sided adhesive products during storage. They must moreover exhibit sufficient antiadhesive effect.
The prior art, e.g. EP 1 277 802 A1 or EP 0 769 540 A2, has previously disclosed release films which have been siliconized at least on one side in order to achieve good release effect.
However, the release effect of the known release films is insufficient for some technical applications where the requirement is to provide a peelable protective film to materials which exhibit strong adhesion even at ambient temperature, the result being that when adhesive products of this type are handled, in particular during the removal of the release film, difficulties arise in the peeling process.
The prior art attempts to improve the release effect of conventional release films in relation to materials of this type exhibiting strong adhesion by equipping the release films with an embossment structure. A disadvantage, for release effect, with provision of this type of embossment structure is that the embossment structure can be damaged on exposure to pressure, e.g. in a roll, under tension and/or under thermal stress, e.g. during stages of further processing, and the release film exhibits inadequate release effect at least at the damaged sites.
There is therefore a need for release films which in particular exhibit very good release effect in relation to strongly adhesive materials, despite the lack of any embossment structure in the release film.
It was therefore an object of the present invention to provide release films which have no embossment structure and which feature improved release effect in relation to adhesives and/or in relation to adhesive materials which exhibit high adhesion even at ambient temperature.